Wheel brake construction



Jan. 2z, 1935.

' J. 'o.'| '-!E|N zE WHEEL BRAKE- CONSTRUCTION Filed sept. 9, 1932 2 Sheets-Sheet` 1 INVENTOR J. Q. HEINZE WHEEL BRAKE CONSTRUCTION Filed Sept. 9, 1932 2 Sheets-Sheet 2 INVENTOR /ezge,

ATTORNEYS Jan. 22, 1935.

Patented Jan. 22, ,2192.35 I l t l UNITED STATES PATENT OFFICE l John 0. Heinze, Detroit, Mich., assigner to HeinzeDevelopment Company, a corporation of Michigan Application September 9, 1932, Serial No. 632,402

8 Claims. (Cl. 18S-1152) This invention relates to a wheel brake mecha.- the usual hub 2 mounted upon the axle shaft 3, nism, and more particularly to an internal brake which in turn, is mounted in bearings within the construction particularly adaptable to wheels of usual xed axle housing 4. The hub 2 is provided 'motor vehicles. with the usual outstanding flange 5 to which the 5 vAn object of the invention is to provide a comspoke assembly is secured in the usual manner,

bined brake drum and housing especially adapted and secured to this flange in any suitable manner, for -the application thereto of internal brake as by the bolts which secure the spoke assembly mechanism to be operated by -fluid under presthereto, isthe outer'side member or side wall 6 sure, the arrangement being such as to provide of the brake drum which comprises this memdouble braking action upon opposite sides of the ber `6 and a similar member 7 forming the oplo drum by an expanding action or movement in posed or inner side wall of the drum, these memopposite directions of brake shoe elements, upon bers being each formed with a peripheral flange 8 application of fluid pressure witllin said brake to oppose a like flange on the other member, said Y shoe structure. A further object is to provide an ilanges being perforated to receive bolts 9 `for arrangement whereby braking force will be apsecuring the inner member v'7 to the periphery l5L plied laterally` of the drum in opposite directions of the outer member 6, said members together and ayieldable wedging action secured to increase thus forming a hollow drum having opposed side the effective braking force. walls. It is also an object to provide an arrangement At a short distance radially outward from the whereby braking force will be automatically ap-l inner edge of its sidewall, each drinn wall is bent 20 plied should uid pressure fail for any reason, or formed inwardly toward the opposed wall, such as the breaking of or leakage in the line, forming each wall with an inclined portion l10 and to provide an arrangement of elements whereextending inwardly of the hollow drum land raby the braking surfaces are effectually cooled by dially outward, and each wall is then formed with air now. under pressure, this same air now being a comparatively sharp annular bend 11, these 25 controllable to effect the setting or releasing of bends of the opposed walls being spaced apart, the brakes. and from these bends the walls are continued It is also an Object t0 Provide a Very compact outwardly of the drum in a sweeping curve which and eillcient arrangement not liable to get out of is substantially semi-circular in cross section,

order or become broken by external impact in forming a hollow annular rib or channel 12 on 3o e use, and wherein the drum forms an enclosing each wall outwardly of the drum from the bends housing to protect the internal parts from dirt 11, and the .outer sides or which drum wallsare and consequent wear.A a continued radially outward as at 13 and then With the above and other ends in view, the inbent inward as at 14 to meet the flanges 8 and vention resides in the matters hereinafter set form a hollow annular chamber at the periphery 35 forth and more particularly-pointed out in the of the drum, outwardly from the opposed hollow Aellirended claims, reference being had to the acribs or annular channels 12, the side walls of each compe-Dying drawings. in Which; of which ribs or channels 12 are, in cross section, Figure 1 is a Vertical aXi section through a' inclined outwardly of the drum and toward each Wheel structure. its hub and axle, and showing, other to form internal annular inclined and o p- 40 as applied thereto and in section, a brake drum posed friction or contact surfaces for the engageand internal brake mechanism within said drum, ment therewith of outer friction members or muillustrative of an embodiment of the present intilated bands 15 hereinafter described, I Venticn, together With air Supplying means illus- 'Within this hollow brake drum or casing formed trated diagrammatically: by the two members 6 and 7, are like and op- 45 Fig. 2 is a View of the inner end of the brake posed annular members 16 forming brakeV shoes drum, showing the same partly in elevation and each formed with a hollow annular rib or channel Partly broken away t0 disclose the internal con- 17, conforming in cross sectional shape to the vstruction, the axle being ShOWn in CI'OSS Section; cross sectional shape of the hollow annular ribs and or channels 12 on the opposed walls of the drum, 50

Fig. 3 is a detail view of a portion of the drum and these annular projections 17 on said shoes `16, A and internal brake shoes in section substantially project into the hollow ribs or annular channels upon the line 3-3 of Figure 1. l 12 with a space therebetween in which spaces` As shown in Figure l, an automobile road wheel are located the friction membersr or bands 15 t 1 of the `usual construction is shown'as having which are rigidly securedv to the opposite outer 5| 12 and into frictional contact with which the of said springs abut the outer faces of the shoes friction bands 15 of the internal shoes are brought Iby a movement of these shoes toward the opposed drum walls, a wedging action of the hollow ribs or channels 17 of the shoes, is secured within the drum channels 12, thus making the braking action more effective with less p'ower required to effect such braking action.--Also release of the shoes from engaged position is more quickly effected due to this wedge construction and with less movement of the shoes.

The opposed shoes 16 are spaced apartl Within the drum with their peripheral outer edges in sliding contact with the portions 14 of the drum walls, and these shoes are of such internal diameter that they t at their inner edges and slide upon the peripheries of a ange member 18 se' cured to the end of the ilxed axle housing 4 and upon a ring 19 secured by bolts 20 to the inner side of said flange, the abutting 'faces of said ring and flange being formed with peripheral mating grooves to receive an anchoring ring 21 which is rigidly held insaid grooves by beingy clamped between said flange and ring 19 when said ring is secured in'place by the bolts 20. 'I'his anchor ring 21 projects radially outward beyond'the faces of flange and ring 19 upon which said shoes slide toward and from each other, and in this anchoring ring is a series of holes to receive a series of pins 22, each pin having an elongated cylindrical head 23 at one end to engage a series of openings in the shoes, and further assist in guiding said shoes in their movement toward and from each other, said head 23 on'certain of said pins engaging openings in one shoe, and these heads on adjacent pins of the series, engaging the openings therefor in the other shoe, and sleeved upon the shank of each pin, is a coiled spring 24 abutting at one end a collar 25 held upon the end of the pin shank in any suitable manner, as by a cotter pin, and the opposite ends where the shanks of the pins pass therethrough, these springs on the pins extending in one direction, thus serving to yieldingly force one shoe laterally in one direction, and the springs on the .set of pins extending in the other direction, serving to yieldingly press the other shoe laterally in the opposite direction. The two shoes are thus yieldingly pressed toward each other by said springs and are normally held with their friction bands Al out of contact with the adjacent surfaces of the drum. f

The space between the adjacent sidesA of the shoes 16, forms an air chamber 26 into which air under pressure is introducedin a man ner hereinafter set forth, through a pipe 27 formed integral with the flange 18, and this air so introduced into said chamber, will force said shoes 16 apart against the action of said springs 24 to bring the friction members 15 carried by said shoes, into contact with the inclined sides of the hollow ribs 12 on the drum walls, thus causing the annular projecting ribs 17 on said shoes, to wedge within said ribs 12 and create strong frictional contact of shoes with drum to give the de-l sired braking action.

Centrally within the drum and between the shoes 16, is secured an annular fixed brake plate 28 by placing its peripheral portion between the anges 8 of the drum and rigidly fastening it in place by means of the bolts 9 which are passed through openings in saidplate, and this plate is formed near its inner edge with annular wedge ribs 29 which project laterally from the'sides of the plate in opposite directions, and, in cross section, are of substantially V-shape to wedge into the hollow ribs or channels 17 of the two brake shoes. The inclined side faces of these ribs 29 thus form fixed friction surfaces to be engaged by interrupted bands or friction members 30 secured upon the inner sides of the inclined side walls of the hollow ribs 17 on the brake shoes 16, and therefor, whenever air pressure in the chamber 26 between the brake shoes is discontinued for any reason, the springs 24 will act to ,n move said shoes toward each other and bring Air under pressure may be supplied in any suit- I able manner from any suitable source, to maintain a certain amount of pressure in the chamber 26 and thus hold the shoes 16 in free or mid position, but it is preferable that a continuously operating device, such as a pump 31 driven by the vehicle engine 32, as illustrated diagrammaticallyin Figure 1, be provided, so that air pressure in said chamber may not only be maintained, but so that there may be a constant ow of air into said chamber and out at the periphery thereof, through small openings or notches 33 formed in the peripheries of the shoes 16, this flow of air to said chamber from said pump, being controlled by a suitable manually operable valve 34 so that the pressure in said chamber may be accurately regulated to provide just sumcient pressure to hold the said shoes in mid position and free, and to increase the pressure to move said shoes .into contact with the drum. Should pressure in said chamber be discontinued .due to the breaking of the air supply line or -bands 15, each of these bands is made up of a plurality of short sections with spaces 35 between the ends of adjacent sections, as shown in Figure 3, and therefore the air forced into said chamber may flow through lsaid chamber past the friction members 30 which are likewise made up of a plurality of spaced sections, thence out and out through the central opening of the drum wall 'I at one side, and through openings 36 in the drum wall 6 at the other s e. members and surfaces, are the efore eiectually cooled by this iiow of air which is maintained by the air pump 31, and all parts of the brake shoes are cooled, the arrangement of the drum members 6 and '7 also providing a casing to direct this air flow and to enclose and protect the internal brake parts from dirt and against external impact blows. Further, the ,conguration in cross section of both thehollow annular ribs or channels 12 and 17, is such as to provide a slight yielding of the walls of these channels when the shoes are forced laterally by heavy air pressure into braking position, thus increasing the rm frictional contact of the friction members with the -inner surfaces of the drum channels, and by the arrangement of the internal brake member 28, .this brake is automatically applied 'by the springs 24. upon failure from any cause,'of air pressure withinthechamber26.

Obviously changes may be Vmade in the con'- struction andv arrangement of parts, within-the scope ofthe appended claims, without departing from the spirit of the invention, and I do not, therefore limit myself to the particular construction shown.

Having thus fully described my invention. wha

-Iclaimis:

' 1. In a brake mechanism, the combination of a rotatable drum having opposedxwalls, a pair'of non-rotatable annular membersln said drum independently movable toward and from each other 'into and out of engagement with said walls, a

member carried by said drum and positioned between said non-rotatable members to be engaged by said members upon movement thereof toward each other, and means for yieldingly holding said members out -of contact withv said walls, said members being moved against the action of said means by uid under pressure.

2. 1n abi-axe mechanism, the edmbmauon om rotatable drum forming an enclosure for internal brake instrumentalities'including non-rotatable means within said drum to frictionally engage said drum and forming'an air chamber, and means for introducing a continuous flow of air under pressure into and through said chamber to operate said non-rotatable meansA and effect a cooling of said instrumentalities.

3. In a brake mechanism, the combination of a rotatable drumv forming -a casing for internal brake instrumentalities including a pair of' mem' bers having friction means to engage-said drum sidesthereonabrakememberiixedtosa'iddrum 'I'he friction the combination of to be engaged by said friction means on one side of said movable brake member, and means for introducing air under pressure into the space between said movable and xed members tol normally hold said movable member with its fric-l tion means out of contact with said xed member and to move said movable member to bring its friction means into contact with said drum.

5. In a brake mechanism, the combination with a rotatable drum forming a casingjto enclose internal brake instrumentalities including a pair friction members to engag opposed walls of said `drum and to form between said members, anair .of spaced apart non-rotatable,.lateral1y movable I lar projecting portion to engage within said annular portions of said drum walls. an annular member xed vto said drum and projecting inwardly thereof between said laterally movable members and formed with annular projections so'A to engage within said annular portions ofJ said laterally movable members, and yieldable means to urge said laterally movable members toward -Sait! member xed t0 said drum.

7. In a brake mechanism, the combination with a rotatabledrum forming a casing for internal. brake instrumentalities including non-rotatable and laterally movablebralre shoes within said drum engaging. at their outer edges, said drum and at their inner edges, a xed support to form an air chamber between said shoes, said shoes being formed at theirouter edges to permit a restricted ow of air from said chamber into said drum, said shoes being provided at their outer sides, with spaced apart-friction members to engage opposed walls of said drum, yieldable means for moving said shoe members' each other, and means for introducing air under pressure into said chamber. v

8. 'Ihe combination with a wheel hub and a fixed axle of a motor vehicle. of a brake drum forming a casing to enclose internal brake instrumentaliti and having opposed side walls with oneofsaidwalls securedtosaidhub,apair of annular brake'shoes in said drum with their inner edge portions engaging and slidable upon an annular supportsecured to said axle, said shoes forming between them, an'air chamber.. spaced apart friction members on the outer side of each of said shoes to engage said side walls of said drum, an annular brake member secured adjacent its periphery to said drum and projecting into said airchamber'between said shoes, friction members on the inner sides of said shoes t'o engage said annular brake-memben yieldable means to move said shoes toward said brake 

